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9mm 158 Grain Options

Posted: 10 Sep 2018 07:32
by Macd
With the summer winding down I am getting back to the bench. Several projects need completing but I am starting a new one to try to increase the performance of my 9mm in knocking over steel targets during matches. My M&P 9 needs bullets no larger than .356 or I get chambering issues. I have two molds for my 38/357 in 158 grains that with sizing will add significantly to impact oomph over my standard 124 grain cast if I can develop a decent load. Has anyone used this weight bullet and do you have any pet loads to share?

Re: 9mm 158 Grain Cast

Posted: 10 Sep 2018 07:56
by farmerjim
I have used the Lyman 358311 in my older 9mm's. I had to have my M&P 9 throated to get it to chamber anything larger than .355. You may want to consider this If you can't find one. I use the Lee 358-125-RF sized to .357 for most of my 9mm. The Lee 358-158-RF may work if you don't get leading at .356.
I have some of these, but have never tried them in my M&P, may have to give them a try.

Re: 9mm 158 Grain Cast

Posted: 10 Sep 2018 16:27
by GasGuzzler
How much OAL room do you have? Seating depth vs powder room and choice might be an issue. There's a recently replied to topic on the 13X grain 9mm RD uses.

Re: 9mm 158 Grain Cast

Posted: 11 Sep 2018 07:16
by Macd
I saw that thread and considered posting in it but felt like I would be hijacking so started a new one. I am going to do some dry loading today to check OAL, seating depth and run some QuickLoad comparisons. The 9mm is not a forgiving case and I am not interested in battering my pistol with +P loads.

Re: 9mm 158 Grain Cast

Posted: 11 Sep 2018 10:41
by Macd
Finished first steps. Both bullets resized to .356 in a Lee sizer. Pistol is a S&W M&P9. Chamber and magazine fit confirmed. Case length is .747.

Quickload Predictions
158-2R OAL 1.174 Seating Depth .286
VV340 3.7G 28,559 PSI 922 FPS
W231 3.5G 31,560 PSI 920 FPS
Bullseye 3.3G 29,347 PSI 946 FPS
Unique 3.8G 29,482 PSI 965 FPS

158-SWC OAL 1.150 Seating Depth .248
VV340 4.1G 29,161 PSI 963 FPS
W231 3.7G 28,916 PSI 926 FPS
Bullseye 3.6G 28,884 PSI 975 FPS
Unique 4.1G 28,501 PSI 987 FPS

I compared these pressures to those listed and predicted for my current TL356-124-2R and they are a bit higher but with one exception 5,000 PSI below SAAMI max of 35,000 PSI. This should mean no problems with cycling. For those who may not be familiar with Quickload it only PREDICTS pressures and performance. The above loads are not yet ready for the trial stage until I do some online research on loading heavier bullets in the 9mm. DO NOT USE.

As a side observation, notice how bullet shape affects seating depth and pressures. The SWC generally speaking gives higher velocity with more powder at lower pressures because it has less seating depth. The VV340 load for the SWC was higher pressure as I was able to add more powder and stay within 100% case capacity. I will most likely drop it 0.1 grains for testing.

Re: 9mm 158 Grain Cast

Posted: 12 Sep 2018 04:48
by GasGuzzler
I'm surprised the cases don't bulge from the wedge shaped brass if you seat deep enough for the OAL to fit.

Re: 9mm 158 Grain Cast

Posted: 12 Sep 2018 06:46
by Macd
GasGuzzler wrote:I'm surprised the cases don't bulge from the wedge shaped brass if you seat deep enough for the OAL to fit.
I think the sizing to.356 helps in this regard. Both pass the drop test. Here are the two bullets loaded to the depths noted above.
(MM 158 Grain.jpg

Re: 9mm 158 Grain Cast

Posted: 12 Sep 2018 08:20
by Macd
At the velocities predicted by QL I can obtain a "Power Factor" for IPSC of 152 and 155 for the 158 grain RN and SWC respectively compared to 132 for my current 124 grain RN or the published maximum 146 for the 147 grain cast. This incidentally has a pressure just under the SAAAMI maximum. My goal is to get to 158 which translates to 1000 FPS with the 158 grain bullet. I do not believe pressure will be the limiting factor but rather space for suitable powder in the case.

Re: 9mm 158 Grain Cast

Posted: 12 Sep 2018 16:49
by GasGuzzler
OK so we're on the same page. You got the bullet all the way in there without a bulge like I wondered but now it's a powder choice like wondered.

I'm fascinated mostly because I tried the opposite early in my reloading career......358" in 9mm cases to fit the throats and forcing cone of a Blackhawk with a 9mm cylinder. My results were poor.

Different project I know.

Re: 9mm 158 Grain Cast

Posted: 12 Sep 2018 19:52
by Macd
I have decided to start with VVN340 as it gives the best velocity and fill/pressure ratio. If the weather co-operates I will try tomorrow and report results.